First report of Melampsora dimorphospora on white willow in Pakistan
During a uredinological survey carried out in September 2012 in the Ushu valley of Swat district, Pakistan, leaves of the medicinally important tree Salix alba L. commonly known as white willow, were found to be infected with a rust fungus. Uredinia were abaxial, scattered, rounded and brownish yellow. Urediniospores were found of two different types: one type of urediniospores were observed to be subglobose, golden brown in color, 18–23 × 18–27 μm with hyaline spore walls of to 2.5 μm thickness, echinulated with obscure germpores. A second type of urediniospores were found, subglobose to broadly ellipsoidal, catenulate in short chains, (22–) 27–33 × 28–36 μm with dark brown, 2.5–3.5 μm thick, verrucose spore walls, germ pores were up to 2, tending to be equatorial. Paraphyses were numerous, intermixed, capitate to clavate, 20–26 × 30–47 μm with up to 4 μm thick wall. Based on these morphological traits and dimorphic urediniospores, the rust was identified as Melampsora dimorphospora S. Kaneko & Hirats, a sample of which was deposited in LAH Herbarium (LAHAM20006) of the University of the Punjab, Lahore. It has previously been found on Salix koriyanag Kimura (Koriyananagai) from Japan (Hiratsuka et al. 1992). To the best of our knowledge, it is a new record for Pakistan.
The authors are highly obliged to the Higher Education Commission (HEC) of Pakistan for funding this research.
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